The Collaborative International Dictionary of English v.0.48:

Tabes \Ta"bes\ (t[=a]"b[=e]z), n. [L., a wasting disease.]
   (Med.)
   Progressive emaciation of the body, accompanied with hectic
   fever, with no well-marked local symptoms.
   [1913 Webster]

   Tabes dorsalis (t[=a]"b[=e]z d[^o]r*s[=a]"l[i^]s) [NL.,
      tabes of the back], locomotor ataxia; -- sometimes called
      simply tabes.

   Tabes mesenterica[NL., mesenteric tabes], a wasting disease
      of childhood characterized by chronic inflammation of the
      lymphatic glands of the mesentery, attended with caseous
      degeneration.
      [1913 Webster]

WordNet (r) 3.0 (2006):

tabes dorsalis
    n 1: syphilis of the spinal cord characterized by degeneration
         of sensory neurons and stabbing pains in the trunk and legs
         and unsteady gait and incontinence and impotence [syn:
         tabes dorsalis, locomotor ataxia]